Danish M/1957 feltperiskop (trench periscope)

I have recently rediscovered an item in my collection. My M/1957 trench periscope (feltperiskop). An ingenious little design. Intended to be used together with the US style entrenching tool.The pouch is a later version. Originally they came in a webbing pouch. Currently I have no idea how many was issued, and how many was kept in stores.